[layer] enable mixed precision - reshape_layer

enable mixed precision on reshape layer
- reshape layer only change dim, so change dimensions and check datatype

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: Donghak PARK <[email protected]>

nntrainer/layers/reshape_layer.cpp

@@ -42,7 +42,7 @@ void ReshapeLayer::finalize(InitLayerContext &context) {
   }
 
   out_dim.batch(in_dim.batch());
-
+  out_dim.setDataType(context.getActivationDataType());
   context.setOutputDimensions({out_dim});
 }